The present invention relates to an imaging device, and, for example, to an imaging device having pixel units arranged in a lattice form.
In an imaging apparatus such as a camera or the like, a CCD or a CMOS sensor is used as an imaging device, and an image acquired by the imaging device is outputted as imaged data. This imaging apparatus is often equipped with an autofocus function of automatically enhancing the sharpness of an image to be photographed. There is known a phase difference system as a system for realizing the autofocus function.
In the phase difference system, a pair or two pairs of light receiving units are provided for each microlens arranged two-dimensionally, and the light receiving units are projected onto the pupil of an imaging optical system by the microlenses to thereby split the pupil. Then, in the phase difference system, object images are respectively formed using two luminous fluxes passed through portions different in terms of the pupil of the imaging optical system. A positional phase difference between the two object images is detected based on the output of the imaging device and converted into a defocus amount of the imaging optical system. An example of such an imaging apparatus having the autofocus function of the phase difference system has been disclosed in Patent Document 1.